Modulating device for recording pilot signals

Abstract

In a device or a recording apparatus for converting n-bit data into m-bit data with different conversion methods, and selecting and outputting one of a plurality of converted m-bit data, when controlling output means in accordance with the plurality of m-bit data, a specific signal component is extracted from each of the plurality of m-bit data, the absolute values of the plurality of extracted outputs are obtained, and at least one of the plurality of absolute values or the extracted output corresponding thereto is selectively output (recorded). Thus, superposition and suppression of a specific frequency component can be realized by a single circuit having a very simple circuit configuration. As a result, the size and the cost of a digital signal recording apparatus utilizing a modulation circuit of this kind can be reduced.

What is claimed is: 
     
       1. A digital modulating device, comprising: conversion means for converting n-bit data into a plurality of m-bit data which are different from each other;   output means for selecting and outputting one of the plurality of m-bit data output from said conversion means; and   control means for controlling said output means in accordance with the plurality of m-bit data, said control means comprising a plurality of extraction means for extracting a specific signal component from each of the plurality of m-bit data, a plurality of absolute-value calculation means for obtaining the absolute values of outputs from said plurality of extraction means, and switching means for selectively outputting (i) the outputs of said plurality of absolute-value calculation means and (ii) the outputs of said plurality of extraction means to be output to said plurality of absolute-value calculation means.   
     
     
       2. A device according to claim 1, wherein said switching means comprises a plurality of switching means, each of which selectively outputs (i) the output from one of said plurality of absolute-value calculation means and (ii) the output from one of said plurality of extraction means. 
     
     
       3. A device according to claim 2, wherein said control means further comprises selection means for controlling the selection operation of said output means so that a plurality of outputs from said plurality of switching means are supplied and the smallest output from among the plurality of outputs is selected. 
     
     
       4. A device according to claim 1, wherein said switching means outputs the output from said absolute-value calculation means or the output from said extraction means by periodically switching the outputs. 
     
     
       5. A device according to claim 1, wherein said control means further comprises a plurality of second extraction means for extracting a second specific signal component different from the specific signal component from each of the plurality of m-bit data, second absolute-value calculation means for obtaining the absolute value of an output from at least one of said plurality of second extraction means, and second switching means for selectively outputting the output from said second absolute-value calculation means and the output from the corresponding second extraction means. 
     
     
       6. A device according to claim 5, wherein said control means further comprises a plurality of addition means to which a plurality of first outputs from said switching means and a plurality of second outputs from said second switching means are supplied, and wherein the selection operation of said output means is controlled so that the smallest output from among outputs from said plurality of addition means is selected. 
     
     
       7. A device according to claim 5, wherein said second switching means outputs the output from said second absolute-value calculation mean or the output from said second extraction means by periodically switching the outputs. 
     
     
       8. A device according to claim 7, wherein when said second switching means output the output from said second extraction means, said switching means not outputting the output from said extraction means. 
     
     
       9. A digital modulating method, comprising the steps of: converting n-bit data into a plurality of m-bit data which are different from each other;   extracting a specific signal component from each of the plurality of m-bit data output as a result of the conversion;   obtaining the absolute value of each of the plurality of extracted specific signal components; and   outputting one of the plurality of m-bit data by selectively using (i) the plurality of absolute values and (ii) the plurality of specific signal components, said outputting step comprising the steps of (a) selecting one of (i) the plurality of absolute values and (ii) the plurality of specific signal components and (b) outputting one of the plurality of m-bit data in accordance with the selection.   
     
     
       10. A method according to claim 9, wherein m-bit data corresponding to the smaller one of the selected absolute value and the specific signal component is output. 
     
     
       11. A method according to claim 9, wherein the absolute value or the specific signal component is output by being periodically switched. 
     
     
       12. A digital modulating device, comprising: modulation means for modulating digital data to obtain a plurality of modulated data having different modulation results from each other;   output means for selecting and outputting one of the plurality of modulated data modulated by said modulation means; and   control means for controlling said output means in accordance with the plurality of modulated data output by said modulation means, said control means including (i) extraction means for extracting specific signal components from each of the plurality of modulated data, (ii) first generation means for generating data indicating amplitudes of the plurality of extracted signal components, and (iii) second generation means for generating data indicating powers of the plurality of extracted signal components, said control means controlling said output means by (a) selecting one of (i) the data indicating the amplitudes of the plurality of extracted specific signal components and (ii) the data indicating the powers of the plurality of extracted specific signal components and (b) controlling said output means in accordance with the selected data.   
     
     
       13. A device according to claim 12, wherein each of the data indicating the amplitudes and the data indicating the powers comprises a plurality of data corresponding to a plurality of outputs from said modulation means, and wherein one of (i) the plurality of data indicating the amplitudes and (ii) the plurality of data indicating the powers are selected by said control means for controlling said output means. 
     
     
       14. A device according to claim 12, wherein modulated data corresponding to a smaller one of the data indicating the amplitudes and the data indicating the powers selected from a plurality of selected data indicating the amplitudes or a plurality of selected data indicating the powers is output. 
     
     
       15. A device according to claim 12, wherein the data indicating the amplitudes and the data indicating the powers is output by being periodically switched. 
     
     
       16. A digital signal recording apparatus, comprising: conversion means for converting n-bit data into a plurality of m-bit data which are different from each other;   recording means for selecting one of the plurality of m-bit data output from said conversion means and recording the selected data on a recording medium; and   control means for controlling the selection operation of said recording means in accordance with the plurality of m-bit data, said control means comprising a plurality of extraction means for extracting a specific signal component from each of the plurality of m-bit data, a plurality of absolute-value calculation means for obtaining the absolute values of outputs from said plurality of extraction means, and switching means for selectively outputting (i) the outputs of said plurality of absolute-value calculation means, and (ii) the outputs of said plurality of extraction means to be output to said plurality of absolute-value calculation means.   
     
     
       17. An apparatus according to claim 16, wherein said recording means records the m-bit data while intermittently forming a large number of tracks on the recording medium. 
     
     
       18. A device according to claim 17, wherein the absolute value or the specific frequency component is output by being periodically switched with a period of formation of tracks by said recording means. 
     
     
       19. A digital signal recording apparatus, comprising: modulation means for modulating digital data to obtain a plurality of modulated data having different modulation results from each other;   recording means for selecting one of the plurality of modulated data modulated by said modulation means and recording the selected data on a recording medium; and   control means for controlling the selection operation of said recording means in accordance with the plurality of modulated data, said control means including (i) extraction means for specific signal components from each of the plurality of modulated data, (ii) first generation means for generating data including amplitudes of the plurality of extracted signal components, and (iii) second generation means for generating data indicating power of the plurality of extracted signal components, said control means controlling the selection operation by (a) selecting one of (i) the data indicating the amplitudes of the plurality of extracted specific signal components and (ii) the data indicating the powers of the plurality of extracted specific signal components and (b) controlling the selection operation in accordance with the selected data.   
     
     
       20. A digital modulation device comprising: conversion means for converting n-bit data into a plurality of m-bit data which are different from each other;   output means for selecting and outputting one of the plurality of m-bit data converted by said conversion means; and   control means for controlling said output means in accordance with the plurality of m-bit data, said control means comprising a plurality of extraction means for extracting a specific signal component from each of the plurality of m-bit data, and a plurality of absolute-value calculation means for obtaining the absolute values of outputs of said plurality of extraction means, said control means controlling said output means by using the outputs of said plurality of absolute-value calculation means and the outputs of said plurality of extraction means to be output to said plurality of absolute-value calculation means, said control means periodically changing between selection of (a) the outputs of said plurality of absolute-value calculation means and (b) the outputs of said plurality of extraction means to be output to said plurality of absolute-value calculation means.   
     
     
       21. A device according to claim 20, wherein the device has a first mode in which said control means controls said output means by using only the outputs of said plurality of absolute-value calculation means, and a second mode in which said control means controls said output means by using only the outputs of said plurality of extraction means to be output to said plurality of absolute-value calculation means, the device further comprising means for periodically setting the mode of the device between the first mode and the second mode. 
     
     
       22. A device according to claim 21, wherein said control means controls said output means so as to output the said m-bit data corresponding to the smallest output among the outputs of said plurality of absolute-value calculation means in the first mode, and to output the m-bit data corresponding to the smallest output among the outputs of said plurality of extraction means in the second mode. 
     
     
       23. A device according to claim 20, wherein said control means has (i) a plurality of second extraction means for extracting a second specific signal component, different from the specific signal component, from each of the plurality of the m-bit data, and (ii) a plurality of second absolute-value calculation means for obtaining the absolute values of outputs of said plurality of second extraction means. 
     
     
       24. A device according to claim 23, wherein said control means further controls said output means by using the outputs of said plurality of second absolute-value calculation means and the outputs of said plurality of second extraction means to be output to said plurality of second absolute-value calculation means. 
     
     
       25. A device according to claim 24, wherein said control means periodically changes usage of the outputs of said plurality of second absolute-value calculation means and the outputs of said plurality of second extraction means to be output to said plurality of second absolute-value calculation means. 
     
     
       26. A device according to claim 20, further comprising recording means for recording the m-bit data output by said output means. 
     
     
       27. A device according to claim 26, wherein said recording means records the m-bit data while intermittently forming a large number of tracks on the recording medium. 
     
     
       28. A device according to claim 27, wherein said control means changes the usage of the outputs of said plurality of absolute-value calculation means and the outputs of said plurality of extraction means to be output to said plurality of absolute-value calculation means at a predetermined period related to a period of formation of the tracks by said recording means. 
     
     
       29. A digital modulation device comprising: modulation means for modulating digital data to obtain a plurality of modulated data having different modulation results from each other;   output means for selecting and outputting one of a plurality of modulated data modulated by said modulation means; and   control means for controlling said output means in accordance with the plurality of modulated data, said control means comprising (i) a plurality of sine component extraction means for extracting a sine signal component of a specific signal from each of the outputs of the plurality of modulated data, (ii) a plurality of cosine component extraction means for extracting a cosine signal component of the specific signal from each of the outputs of the plurality of modulated data, (iii) a plurality of first absolute-value calculation means for obtaining the absolute values of outputs of said plurality of sine component extraction means, and (iv) a plurality of second absolute-value calculation means for obtaining the absolute values of outputs of said plurality of cosine component extraction means,   wherein the device has a first mode in which said control means controls said output means according to outputs of both of said plurality of first and second absolute-value calculation means, and a second mode in which said control means controls said output means according to the outputs of said plurality of sine component extraction means and the outputs of said plurality of second absolute-value calculation means.   
     
     
       30. A device according to claim 29, further comprising recording means for forming a plurality of tracks on a recording medium to record the modulated data on the plurality of tracks. 
     
     
       31. A device according to claim 30, wherein said recording means forms a first kind of plurality of tracks on which the modulated data having a small amount of the specific signal component are recorded in the first mode and forms a second kind of plurality of tracks on which the modulated data having a greater amount of the specific signal component are recorded in the second mode. 
     
     
       32. A device according to claim 29, wherein said modulation means modulates the digital data by using an interleaved NRZI method.